1. Field of the Invention
The present invention relates to optical fiber assemblies used to connect surgical laser instruments to a laser source and, more particularly, to an adjustable, detachable optical fiber assembly which can be used to connect a surgical instrument such as a slit lamp or operating microscope to a laser source.
2. The Prior Art
The advent of the laser has greatly expanded the frontiers of many areas of science. One of the most significant applications of this new laser technology has been in the field of medicine. Lasers possess many features which make them uniquely adaptable to various types of surgical procedures.
For purposes of surgery, lasers operate on the principle that the highly collimated laser light beam may be converted into thermal energy when focused on a particular point on living tissue. This heat can be used to create incisions, coagulate blood, destroy diseased cells and perform many other functions.
Different types of lasers affect different types of tissues in various ways. For example, the wave length of light produced by a carbon dioxide laser is readily absorbed by water and other body fluids. On the other hand, the light produced by an argon laser readily passes through clear fluids and tissue but is absorbed by pigmented tissue and by colored fluids such as blood.
The ability of the argon laser to pass through transparent fluids and tissue has made it especially suitable for use in various types of ophthalmic surgery. For example, in 1965 doctors first utilized an argon laser to repair a detached retina. The surgeons were able to focus the laser into the interior portion of the eyeball and "weld" the detached retina back into place. At the point where the laser beam struck the retina, the light energy was converted into heat energy which produced a coagulum. During the next few weeks, this coagulum was converted to scar tissue which anchored the retina in place.
Since that time, this procedure has been much improved and the utilization of lasers has become a generally accepted method of repair of this type of abnormality. Surgical laser apparatus has also been used to repair retinal tears and abnormal blood vessels within the eye.
When using a laser to perform ophthalmic surgery, the surgeon often utilizes an instrument which is generally referred to as an operating microscope. The operating microscope is typically mounted above the operating table and is connected to a laser source by means of a flexible optical fiber. Through the operating microscope, the surgeon can obtain a magnified view of the area upon which he needs to perform the surgical operation. The surgeon can then activate the laser source by means of a foot switch and the laser light transmitted through the optical fiber is focused through a series of lenses in the operating microscope onto the point at which the laser needs to be applied.
Many operations have become routine enough that an ophthalmologist can now perform them in his office utilizing what is commonly referred to as a "slit lamp." This device, like an operating microscope, is connected to a laser source by means of a flexible optical fiber. The slit lamp also utilizes a series of lenses to focus the laser beam onto the point at which the surgical operation needs to be performed.
Notwithstanding the substantial advances in ophthalmic surgery which have come about as a result of the use of laser technology, the current state of the art leaves much to be desired. One of the primary concerns faced by doctors and hospitals is the extremely high cost of laser equipment. The laser source, slit lamp and operating microscope are all extremely expensive.
One of the problems which has hindered the use of laser systems and which adds to their cost has been the breakdown of the optical fiber which connects the slit lamp or operating microscope to the laser source. The optical fiber is extremely thin, generally being on the order of about 100 microns in diameter, and is extremely fragile. Accordingly, the fiber is usually encased within a silicone sheath and is then placed within some type of casing for additional protection. Nevertheless, even with the utmost care, a certain amount of degradation of the optical fiber occurs with time. The optical fiber is also subject to accidental breakage and the ends of the fiber can become dirty, thus interfering with the transmission of the laser beam.
Because of the extremely small diameter of the optical fiber, it is important that the laser beam be focused directly onto the tip of the fiber. If the laser beam is not properly aligned with the end of the optical fiber, much of its power can be lost. Additionally, the misdirected beam can vaporize portions of the connector, thus destroying it or creating debris which can obscure the end of the fiber, which also reduces the amount of light which can be transmitted. Accordingly, in the past it has been customary to permanently attach the optical fiber to the laser source in order to achieve and maintain proper alignment of the fiber with the laser output.
In the prior art devices, because the optical fiber is permanently attached to the laser source, if any type of fiber breakdown occurs, the whole unit has to be sent back to the factory for repair. This creates added expense to the maintenance of the laser system and also causes inconvenience. Because it may take a substantial amount of time to have the optical fiber replaced, scheduled operations have to be cancelled and emergency operations cannot be performed unless a back-up laser system is maintained. However, because of the high cost of the laser system, it is extremely expensive and thus often impractical to have a back-up system.
Accordingly, what is needed in the art is a fiber assembly which can be used with slit lamps and the like and which is detachable from both the slit lamp and the laser source for easy replacement or repair. The fiber assembly must also be capable of providing the extremely fine alignment necessary to insure that the laser beam is accurately focused onto the end of the optical fiber.